全文获取类型
收费全文 | 15860篇 |
免费 | 748篇 |
国内免费 | 19篇 |
专业分类
电工技术 | 142篇 |
综合类 | 30篇 |
化学工业 | 3507篇 |
金属工艺 | 318篇 |
机械仪表 | 261篇 |
建筑科学 | 807篇 |
矿业工程 | 74篇 |
能源动力 | 437篇 |
轻工业 | 1497篇 |
水利工程 | 213篇 |
石油天然气 | 50篇 |
无线电 | 956篇 |
一般工业技术 | 2832篇 |
冶金工业 | 3297篇 |
原子能技术 | 116篇 |
自动化技术 | 2090篇 |
出版年
2022年 | 95篇 |
2021年 | 317篇 |
2020年 | 262篇 |
2019年 | 292篇 |
2018年 | 323篇 |
2017年 | 314篇 |
2016年 | 366篇 |
2015年 | 292篇 |
2014年 | 477篇 |
2013年 | 989篇 |
2012年 | 739篇 |
2011年 | 1019篇 |
2010年 | 726篇 |
2009年 | 722篇 |
2008年 | 828篇 |
2007年 | 784篇 |
2006年 | 665篇 |
2005年 | 580篇 |
2004年 | 497篇 |
2003年 | 489篇 |
2002年 | 437篇 |
2001年 | 260篇 |
2000年 | 241篇 |
1999年 | 240篇 |
1998年 | 210篇 |
1997年 | 205篇 |
1996年 | 189篇 |
1995年 | 223篇 |
1994年 | 210篇 |
1993年 | 179篇 |
1992年 | 199篇 |
1991年 | 112篇 |
1990年 | 137篇 |
1989年 | 162篇 |
1988年 | 155篇 |
1987年 | 152篇 |
1986年 | 150篇 |
1985年 | 196篇 |
1984年 | 177篇 |
1983年 | 157篇 |
1982年 | 168篇 |
1981年 | 150篇 |
1980年 | 115篇 |
1979年 | 143篇 |
1978年 | 141篇 |
1977年 | 120篇 |
1976年 | 104篇 |
1975年 | 95篇 |
1974年 | 100篇 |
1973年 | 106篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
1.
Shanshan Zhuang Wenxiong Zheng Yunong Na Naiyi Chen Fan Gong Bingxuan Huang Stephen Brennan Charles Congyi Liu Jian Cheng Lukai Ma Huifan Liu 《International Journal of Food Science & Technology》2022,57(2):1093-1103
The β-Carotene (BC), an important precursor of vitamin A (VA), possesses antioxidant activity but is fat-soluble and has low bioavailability. In previous in-vitro assays evaluating antioxidant and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) free radical scavenging, both BC and VA showed a strong ability to scavenge radicals and protected cells from oxidative stress. Here, we used artificially simulated gastrointestinal digestion and Caco-2 cell absorption models to evaluate the bioavailability of the BC during gastrointestinal digestion and absorption using high-performance liquid chromatography (HPLC) analysis. We observed high absorptive and transfer rates of BC and detected retinol metabolites (Vitamin A). Therefore, BC can be detected in the acidic gastrointestinal environment using HPLC. Optimised method provided better separation of BC and VA in the column, improving the accuracy of the test results. 相似文献
2.
Jean-Claude Malela-Majika Sandile Charles Shongwe Olatunde Adebayo Adeoti 《Quality and Reliability Engineering International》2021,37(8):3314-3322
The sensitivity of a monitoring scheme depends on many factors including the variance of the charting statistic which is very important in the computation of the control limits. This paper discusses the computation of the variance of the recently proposed hybrid homogeneously weighted moving average (HHWMA) scheme which was based on an incorrect assumption. The correct variance is used to evaluate the run-length characteristics of the HHWMA scheme. It is observed that the incorrect variance has a significant impact on the sensitivity (or performance) of the HHWMA scheme. 相似文献
3.
4.
Belcher Calvin H. Zheng Baolong MacDonald Benjamin E. Langlois Eric D. Lehman Benjamin Pearce Charles Delaney Robert Apelian Diran Lavernia Enrique J. Monson Todd C. 《Journal of Materials Science》2022,57(9):5518-5532
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic... 相似文献
5.
Carolyn A. Grimley Stephen Funni Christopher Green Elizabeth C. Dickey 《Journal of the European Ceramic Society》2021,41(4):2807-2817
In flash sintering experiments, the thermal history of the sample is key to understanding the mechanisms underlying densification rate and final properties. By combining robust temperature measurements with current-ramp-rate control, this study examined the effects of the thermal profile on the flash sintering of yttria-stabilized zirconia, with experiments ranging from a few seconds to several hours. The final density was maximized at slower heating rates, although processes slower than a certain threshold led to grain growth. The amount of grain growth observed was comparable to a similar conventional thermal process. The bulk electrical conductivity correlated with the maximum temperature and cooling rate. The only property that exhibited behavior that could not be attributed to solely the thermal profile was the grain boundary conductivity, which was consistently higher than conventional in flash sintered samples. These results suggest that, during flash sintering, athermal electric field effects are relegated to the grain boundary. 相似文献
6.
7.
8.
9.
10.
Qin-yu Zhou Shan Zhao Yan-yan Huang Jin-shuang Hu Jia-hua Kuang Dong-mei Liu Charles S. Brennan 《International Journal of Food Science & Technology》2021,56(6):2992-3003
Yogurt preserves and enhances nutritional value of milk. In this study, we have compared several strains to determine the physicochemical, sensory, rheological and aroma characteristics of different yogurts. We used Lactobacillus gasseri LGZ 1029 (LG), commercial probiotic L. rhamnosus (LGG) and traditional fermentation strains Streptococcus thermophilus and L. bulgaricus (SL). Results showed that the flavour and texture characteristics of mixed-strain yogurts were obviously better than in single-strain yogurts. Addition of LG increased pseudoplastic behaviour, as shown by Herschel–Bulkley model analysis of rheological behaviour. The LG + SL group also had both the highest viscosity consistency index and thickening ability. In addition, a total of 57 volatile compounds were detected in yogurts and the fermentation with the addition of LG was mainly affected by ketones. Our study suggested that a yogurt with new attributes can be produced by using LGZ 1029. 相似文献